This invention relates generally to a liquid-permeable topsheet used in a body fluids absorbent garment such as a disposable diaper, a sanitary napkin or the like.
FIG. 3 of the accompanying drawings is a perspective view exemplarily illustrating a topsheet 100 disclosed in Japanese Laid-Open Patent Application No. Hei4-82977. The topsheet 100 comprises a plurality of first ribs 111 extending in parallel one to another in one direction and a plurality of second ribs 121 extending in parallel one to another so as to intersect the first ribs 111. Each pair of adjacent the first ribs 111 intersect each pair of adjacent the second ribs 121 to define an air- and moisture-permeably opened region 106. The pair of first ribs 111 and the pair of second ribs 121 are in a relationship of warp and weft, i.e., the crests T.sub.x of the first ribs 111 protrude and the crests T.sub.y of the second ribs 121 descend at a pair of diagonally opposed intersections R.sub.3, R.sub.4. At another pair of diagonally opposed intersections R.sub.1, R.sub.2, the crests T.sub.y of the second ribs 121 protrude and the crests T.sub.x of the first ribs 111 descend so as to intersect the second ribs 121 at respective lower portions of their side surfaces. In this manner, the first and second ribs 111, 121 repeat their protruding and descending at a series of intersections arranged longitudinally in respective lines. With such topsheet 100, the ribs 111 protruding at the intersections R.sub.1 .about.R.sub.4 are intended to be put in contact with the skin of a wearer, for example, at their crests T.sub.x and in the proximity thereof and the other ribs 121 having their crests descending at these intersections can be spaced apart from the skin of the wearer. Portions 112, 122 of the ribs spaced apart from the skin of the wearer define a serpentine or zigzag passage between the topsheet and the skin of the wearer as indicated by an arrow F and enable air and/or body fluids to move along the skin of the wearer.
Referring to FIG. 3, the portions 112 of the first ribs 111 intended to be spaced apart from the skin of the wearer, for example, between a pair of transversely adjacent second ribs 121, alternately appear with respect to the respective second ribs 121 so as to define the serpentine or zigzag passage for air and/or body fluids between these two ribs 121. Such serpentine or zigzag passage has a higher flow resistance than a non-serpentine passage and rather prevents air and/or body fluids from rapidly moving therethrough.